JP2017153351A - Non-contact power transmission circuit and non-contact power transmission device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-contact power transmission circuit which can contactlessly transmit electric power from one side (the primary side for transmitting electric power) to the other side (the secondary side for receiving the electric power) and can realize reduction in the size and increase in the efficiency.SOLUTION: The non-contact power transmission circuit includes: coil bodies 41 and 71 around which coils 4 and 7 are discally-wound; magnetic materials 42 and 72 in parallel to the coil bodies 41 and 71; metal magnetism shieling plates 43 and 73 at an outside opposed to an intermediate coil member 21 between the coil bodies 41, 71 and the magnetic materials 42, 72; and an intermediate coil 22 formed of a discally-wound coil body 221 and a magnetic material 222 partially covering the coil body 221, the coil body 221 and the magnetic material 222 being parallel to each other.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a non-contact power transmission circuit and a non-contact power transmission device that send power in a non-contact manner from one side (power supply side: primary side) to the other side (power supply side: secondary side). .

  Non-contact charging technology that uses electromagnetic induction as a non-contact charging technology to send power in a non-contact manner from one side (power supply side: primary side) to the other side (power supply side: secondary side) In addition, a non-contact charging method using magnetic resonance is known. As a power transmission technique using a magnetic resonance method, a non-contact power feeding system disclosed in Patent Document 1 is known. In the technique disclosed in Patent Document 1, a plurality of coils are arranged in parallel as primary and secondary coils, and power is transmitted from the primary coil to the secondary coil using a magnetic resonance method. It has a transmission circuit.

  By arranging a plurality of coils side by side as primary and secondary coils, the primary coil spacing (primary coil width) and secondary coil spacing (secondary coil width) However, the non-contact power feeding system can be applied to, for example, a charging device for an electric vehicle or a bidirectional power transmission device between an electric vehicle and a house.

  On the other hand, as an application of contactless charging technology that sends power in a contactless manner from the primary side to the secondary side, it is applied to power supply to power consuming members installed at high places, for example, power supply to aviation obstacle lights on power transmission towers It is possible. By applying the non-contact charging technology, it is possible to supply power while ensuring an electrical insulation distance. Up to now, when applying a technology for supplying power in a contactless manner to power supply to an aircraft obstacle light of a power transmission tower, an induction current from an overhead ground wire, a storage battery with photovoltaic power generation, or the like has been used. However, when an induced current from an overhead ground wire is used, there is a problem that the voltage rises due to lightning strikes. When a storage battery with photovoltaic power generation is used, work at a high place for maintenance inspection of the storage battery is not possible. It becomes necessary.

  In order to reduce the increase in voltage and work at high places, it is conceivable that a plurality of coils are arranged in parallel as primary side coils and secondary side coils in the magnetic resonance system, and power is supplied to high places without contact. In this case, the coil current is secured from one coil member to the other coil member through the intermediate coil member by appropriately arranging the intermediate coil member between the primary side coil member and the secondary side coil member. And the distance of one coil member of one side and the other coil member of the other side is securable by the total of the distance between each coil member.

JP 2014-217117 A

  However, paying attention to the use of the distance between specific coil members, the other spaces (the width of the primary side coil and the width of the secondary side coil) are useless spaces that lead to an increase in the size of the non-contact power transmission circuit. It becomes. Depending on the field of application of the contactless charging technology, it may be required to reduce the size and increase the efficiency of the contactless power transmission device including the contactless power transmission circuit, which makes it difficult to respond.

  The present invention has been made in view of the above circumstances, and can transmit power in a non-contact manner from one side (power supply side: primary side) to the other side (power supply side: secondary side). Another object of the present invention is to provide a non-contact power transmission circuit capable of realizing miniaturization and high efficiency.

  In addition, the present invention has been made in view of the above situation, and includes a non-contact power transmission circuit that can transmit power from one side to the other side in a non-contact manner, and can be downsized and highly efficient. Another object of the present invention is to provide a non-contact power transmission device.

  In order to achieve the above object, a non-contact power transmission circuit of the present invention according to claim 1 forms a closed circuit with one coil on one side and one capacitor connected in parallel or in series with the one coil. A coil member is formed, and the other coil on the other side and the other capacitor connected in parallel or in series with the other coil form a closed circuit to form the other coil member, while the intermediate coil and the intermediate coil are connected in parallel. A non-contact power transmission circuit in which a closed circuit is formed with an intermediate capacitor to form an intermediate coil member, and a plurality of the intermediate coil members are disposed between the one coil member and the other coil member, wherein the one coil And the other coil includes a coil body wound in a disc shape, a magnetic body arranged in parallel to the coil body, the coil body and the intermediate coil member of the magnetic body, Each of the intermediate coils is arranged in parallel with the coil body, and the coil body is partially arranged on the coil body. It is comprised from the magnetic body to coat | cover.

  In the present invention according to claim 1, in the one coil and the other coil, the metal magnetic shielding plate is disposed on the outer side opposite to the coil body and the intermediate coil member of the magnetic body. It is possible to prevent the shielding plate from going around to the outside opposite to the intermediate coil member, and to prevent leakage.

  In addition, in the intermediate coil, a magnetic body that is arranged in parallel with the coil body and partially covers the coil body is disposed, so that the coupling between the coils is reduced, and the useless space can be greatly shortened. As inductance increases, coil current decreases and Joule loss decreases.

  And the non-contact power transmission circuit of the present invention according to claim 2 is the non-contact power transmission circuit according to claim 1, wherein the magnetic body in the intermediate coil is composed of a plurality of rod-shaped or fan-shaped magnetic bodies. Thus, the plurality of rod-shaped or fan-shaped magnetic bodies are arranged radially.

  In the present invention according to claim 2, in the same manner as the present invention according to claim 1, it is possible to realize a significant reduction in wasted space and a reduction in coil current due to an increase in self-inductance, and a Joule loss. By reducing the power source capacity, it is possible to suppress the power capacity to the minimum necessary, and the cost is excellent.

  In order to achieve the above object, a non-contact power transmission apparatus according to a third aspect of the present invention is configured such that the non-contact power transmission circuit according to the first or second aspect and a direct current power source are connected, and the direct current of the direct current power source is connected. While converting the output voltage into an AC voltage, the one coil is connected and driven as an inverter so that the converted AC voltage is applied to the other coil, and connected to the other coil, And a second power conversion device driven as a converter for converting the AC voltage applied through the other coil into a DC output voltage and applying the DC output voltage to a DC load.

  According to the third aspect of the present invention, a wasteful space between the coils can be significantly shortened, and a small and small capacity inverter and converter can be provided in a state where the coil current is reduced due to the increase of the self-inductance and the joule loss is reduced. Power transmission can be performed.

  In the present invention, electric power can be sent from one side (power supply side: primary side) to the other side (power supply side: secondary side) in a non-contact manner, realizing miniaturization and high efficiency. It is possible to provide a non-contact power transmission circuit that can be used.

  Moreover, in this invention, it is set as the non-contact electric power transmission apparatus provided with the non-contact electric power transmission circuit which can send electric power non-contact from one side to the other side, and can implement | achieve size reduction and high efficiency. It becomes possible.

1 is a schematic system diagram of a contactless power transmission device including a contactless power transmission circuit according to an embodiment of the present invention. It is arrangement explanatory drawing of each coil in a non-contact electric power transmission device, (a) is arrangement explanatory drawing which arranged each capacitor connected to one coil and the other coil in parallel, (b) is connected to one coil and the other coil It is arrangement | positioning explanatory drawing which arrange | positioned each made capacitor | condenser in series. It is the fragmentary perspective view which showed a part of the state which each coil in the non-contact electric power transmission apparatus cut | disconnected each in the thickness direction, (a) is a partial perspective view which shows one coil, (b) is a part which shows an intermediate coil It is a perspective view. It is an equivalent circuit diagram of a non-contact power transmission circuit, (a) is an equivalent circuit diagram in which capacitors connected to one coil and the other coil are arranged in parallel, (b) is each connected to one coil and the other coil It is an equivalent circuit diagram in which capacitors are arranged in series. FIG. 3 is an explanatory diagram of arrangement of each coil according to the first embodiment. It is a graph which shows the relationship between the frequency in Example 1, an electric current, and electric power transmission efficiency. It is a graph which shows the relationship between the frequency in Comparative Example 1, electric current, and electric power transmission efficiency. It is a graph which shows the relationship between the frequency in Comparative Example 2, an electric current, and electric power transmission efficiency. It is a graph which shows the relationship between the frequency in Comparative Example 3, an electric current, and electric power transmission efficiency. It is a schematic system diagram of the non-contact power transmission device provided with the non-contact power transmission circuit of the reference example. It is a graph of the ratio with respect to the fundamental current of the non-contact electric power transmission apparatus of a reference example and an Example. It is a graph which shows the relationship between the frequency of the non-contact electric power transmission apparatus of a reference example and an Example, and the efficiency of a coil. It is a graph which shows the relationship between DC load voltage and the efficiency of a coil of the non-contact electric power transmission apparatus of a reference example and an Example.

  The configuration of the contactless power transmission circuit and the contactless power transmission device of the present invention will be described with reference to FIGS. 1 to 3.

  FIG. 1 is a schematic system for explaining the overall outline of a contactless power transmission device including a contactless power transmission circuit according to an embodiment of the present invention, and FIG. The arrangement of the coil member, the other coil member, and the intermediate coil member is shown. FIG. 3 shows the arrangement of the components of the one coil member and the intermediate coil member. In FIG. 3, for convenience of explanation, each member cut in the thickness direction into a semi-disc shape is shown, but each actual member has a disc shape. In the description, the shape of each member is a disk shape, but is not limited thereto, and may be a square, for example.

  As shown in FIG. 1, the non-contact power transmission device 1 includes a primary side equipment 3 which is equipment (power supply device) on one side (a power supply side: primary side) provided with one coil member 2, and the other coil. The secondary side equipment 6 which is the equipment of the other side (electric power supply side: secondary side) provided with the member 5 is provided.

  As an example of the secondary side equipment 6, for example, it is applied to a charging device for an electric vehicle.

  As shown in FIG. 2A, the one coil member 2 is configured by forming a closed circuit with one coil 4 and one capacitor 8 connected in parallel to the one coil 4, and the other coil member 5 is The other coil 7 and the other capacitor 9 connected in parallel to the other coil 7 form a closed circuit. Alternatively, as shown in FIG. 2 (b), one coil member 2 forms a closed circuit with one coil 4 and one capacitor 8 connected in series to one coil 4, and the other coil member 5 is composed of the other coil. 7 and the other capacitor 9 connected in series to the other coil 7 may form a closed circuit.

  As shown in FIG. 1, the primary side equipment 3 is provided with a DC power supply 11, and an inverter 12 as one power converter is connected to the DC power supply 11, and one coil 4 of one coil member 2 is connected to the inverter 12. It is connected. The inverter 12 is driven so that the DC output voltage of the DC power supply 11 is converted into an AC voltage, and the AC voltage converted through the one coil 4 is applied to the other coil 7.

  The secondary side equipment 6 is provided with a load 15 (DC load: for example, an in-vehicle battery), and a rectifier 16 as the other power converter is connected to the load 15. The rectifier 16 is connected to the other coil 7 of the other coil member 5. It is connected. The rectifier 16 is driven as a converter that converts the AC voltage applied through the other coil 7 into a DC output voltage and applies the DC output voltage to the load 15.

  As shown in FIGS. 1 and 2, two intermediate coil members 21 are arranged between the one coil member 2 and the other coil member 5. The intermediate coil member 21 is configured by forming a closed circuit with an intermediate coil 22 and an intermediate capacitor 23 connected in parallel to the intermediate coil 22. The contactless power transmission device 1 may have any number as long as a plurality of intermediate coil members 21 are arranged, but at least two are preferably arranged, or three or more may be arranged. Adjacent coil members (coils) constitute a resonance circuit.

  In the present embodiment, since the intermediate coil member 21 is disposed between the one coil member 2 and the other coil member 5, in the magnetic resonance system, the one coil member 2 to the other coil via the intermediate coil member 21 (intermediate coil 22). A coil current can be secured toward the member 5.

  Next, the configuration of each coil will be described in detail with reference to FIGS. 1 and 3. As shown in FIGS. 1 and 3A, the one coil 4 includes a coil body 41 wound in a disk shape, a disk-shaped magnetic body 42 arranged in parallel with the coil body 41, a coil body 41, and It is comprised from the metal magnetic shielding board 43 arrange | positioned on the outer side which is the opposite side to the intermediate coil member 21 of the magnetic body 42. FIG. When the magnetic field generated from the coil body 41 reaches the metal magnetic shielding plate 43, an eddy current is generated on the surface of the metal magnetic shielding plate 43, and loss occurs. In the present embodiment, by inserting the magnetic body 42 between the coil body 41 and the metal magnetic shield plate 43, the eddy current loss is reduced and the self-inductance of the coil body 41 is increased so that the coil current is reduced. Can reduce Joule loss.

  On the other hand, the other coil 7 is opposite to the coil body 71 wound in a disk shape, the disk-shaped magnetic body 72 arranged in parallel to the coil body 71, and the intermediate coil member 21 of the coil body 71 and the magnetic body 72. It is comprised from the metal magnetic shielding board 73 arrange | positioned on the outer side which is a side. In addition, since the structure and material of the one coil 4 and the other coil 7 are the same, description of each member of the other coil 7 is abbreviate | omitted suitably.

  In the present embodiment, since the metal magnetic shielding plates 43 and 73 are arranged on the outer side of the coil bodies 41 and 71 and the magnetic bodies 42 and 72 opposite to the intermediate coil member 21, the generated magnetic field is generated by the metal magnetic shielding plate 43. , 73 can be prevented from leaking out to the outside, which is the opposite side to the intermediate coil member 21.

  The coil bodies 41 and 71 have, for example, a litz wire (also referred to as a composite twisted rope layer having a structure in which a plurality of enamel strands are bundled and twisted, and the strand bundles are further twisted) having a diameter r (see FIG. 2). ) Was wound 27 times so as to form a 20 cm disk. The magnetic bodies 42 and 72 are discs having a diameter larger than the diameter r of the coil bodies 41 and 71, and are made of a magnetic material such as ferrite. Furthermore, the metal magnetic shielding plates 43 and 73 are circular plates having a diameter larger than that of the magnetic bodies 42 and 72, and are made of a metal material such as aluminum having a magnetic shielding effect. However, the configurations and materials of the coil bodies 41 and 71, the magnetic bodies 42 and 72, and the metal magnetic shielding plates 43 and 73 can be changed as necessary.

On the other hand, as shown in FIGS. 1 and 3B, the intermediate coil 22 is arranged in parallel to the coil body 221 and the coil body 221, which has the same configuration and material as the coil body 41 disposed in the one coil 4. And a magnetic body 222 that partially covers the coil body 221. The material of the magnetic body 222 is the same as that of the magnetic body 42 disposed on the one coil 4, but the configuration of the magnetic body 222 is different. That is, the magnetic body 222 is composed of, for example, a plurality (eight in this case) of rod-shaped magnetic bodies (bar-shaped magnetic bodies) 224, and these bar-shaped magnetic bodies 224 are arranged in a radial manner, and the coil body 221 is partially covered. It is preferable to cover. The coverage of the magnetic body 222 with respect to the entire coil body 221 needs to be increased as the distance S ₁ (see FIG. 2) between the intermediate coil 22 and the one coil 4 approaches. For example, if the specification of the above, if the distance S ₁ is of 7cm, the coverage may be 0%, but the distance S ₁ is when the close both so that 3 cm, the coverage is 25% It will be necessary. When each of the rod-shaped magnetic bodies 224 is eight rectangular plates having a longitudinal width of 10 cm, a short-side width of 1 cm, and a thickness of 3 mm, the coverage of the magnetic body 222 is expressed by the following formula: As shown in (1), it is approximately 25%.
100 × (8 × 10 × 1) / (π × 10 ² ) ≈25 (1)

  In the present embodiment, since the magnetic body 222 composed of the eight bar-shaped magnetic bodies 224 is radially arranged on the surface of the coil main body 221 in the thickness direction, the useless space can be greatly reduced and the self-inductance can be reduced. Therefore, the coil current can be reduced and the Joule loss can be reduced. Moreover, the capacity | capacitance of the inverter 12 and the DC power supply 11 can be suppressed to the minimum necessary, and it is excellent also in cost efficiency. In the present embodiment, the magnetic body 222 including the eight rod-shaped magnetic bodies 224 is used. However, the magnetic body 222 may be composed of a plurality of fan-shaped magnetic bodies.

FIG. 4 shows an equivalent circuit of the above-described contactless power transmission circuit, where (a) shows an equivalent circuit in which capacitors connected to one coil and the other coil are arranged in parallel, and (b) shows one circuit. The equivalent circuit which has arrange | positioned each capacitor connected to the coil and the other coil in series is shown. In the present embodiment, the capacitors C ₀ and C ₃ may be arranged in parallel or in series as described above. As shown in FIG. 4, in the circuit for transmitting power from the DC power supply 11 to the load 15, the self of each coil (one coil 4, intermediate coil 22, intermediate coil 22, and other coil 7) in order from the transmission side (primary side). The inductance is L ₀ , L ₁ , L ₂ , L ₃ , the winding resistance of each coil is r ₀ , r ₁ , r ₂ , r ₃ , and the resonant capacitors are C ₀ , C ₁ , C ₂ , C _3. Yes.

The coupling coefficient between the one coil 4 and the intermediate coil 22 adjacent to the one coil 4 is k ₀₁ , the coupling coefficient between the intermediate coils 22 is k ₁₂ , and the intermediate coil 22 and the other coil adjacent to the other coil 7 are combined. the coupling coefficient between the 7 k _23, whereas between the intermediate coil 22 and the other coil 7 adjacent the coupling coefficient between the intermediate coil 22 to k _02, whereas the coil 4 which is adjacent to the coil 4 and the other coil 7 K ₁₃ , and the coupling coefficient between one coil 4 and the other coil 7 is k ₀₃ . In the present embodiment, the ratio of the coupling coefficients k ₀₁ , k ₁₂ , and k ₂₃ is approximately 2: 1: 2 by arranging the coils as described above, but the present invention is not limited to this. As long as the power can be transmitted as a whole, the ratio of the coupling coefficients k ₀₁ , k ₁₂ , and k ₂₃ may be slightly different from 2: 1: 2.

  The input impedance viewed from the DC power source 11 and the power transmission efficiency are given based on the relationship between the voltage applied to the coil and the current flowing through the coil, and the mutual inductance can be derived using the coupling coefficient and the self-inductance. . The loss of each coil can be derived from the amount of heat generated based on the current value and the winding resistance of the coil.

In the present embodiment, since each coil has the structure as described above, as shown in FIG. 2, the distance S ₁ between the one coil member 2 and the intermediate coil member 21 is 3 cm, and between the intermediate coil members 21. the distance _{S 2} is 10 cm, the distance _{S 3} between the intermediate coil member 21 and the other coil member 5 are respectively set to 3 cm. However, the distances S ₁ , S ₂ and S ₃ between the coils are not limited to the above values, and can be appropriately changed according to the arrangement of the coils.

  In the non-contact power transmission device 1 including the non-contact power transmission circuit having the above configuration, the DC output voltage from the DC power source 11 is converted into an AC voltage by the inverter 12, and the converted AC voltage is passed through the one coil 4. It is applied to the other coil 7 through the intermediate coil 22. On the other hand, the AC voltage applied to the coil 7 is converted into a DC output voltage by the rectifier 16, and the DC output voltage is applied to the load 15. Thereby, the electric power from the DC power supply 11 is supplied to the load 15 in a non-contact manner by the magnetic resonance method.

  In the non-contact power transmission device 1 including the above-described non-contact power transmission circuit, the intermediate coil 22 is disposed in parallel with the coil main body 221, and the magnetic body 222 that partially covers the coil main body 221 is disposed. Even if the space is greatly shortened, it can be maintained at an appropriate value so that the coupling coefficient does not become excessive, and the coil current decreases due to the increase of the self-inductance and the joule loss also decreases. It is possible to perform power transmission via the inverter and the converter that have been increased in capacity.

  Thereby, it becomes possible to set it as the non-contact electric power transmission apparatus 1 provided with the non-contact electric power transmission circuit which can implement | achieve size reduction and high efficiency.

  Moreover, the non-contact electric power transmission apparatus 1 mentioned above is applicable to the electric power feeding with respect to vehicles which require electric power, such as an electric vehicle.

  The contactless power transmission circuit in the above-described embodiment has been described with reference to an example in which power is supplied from the DC power supply 11 to the load 15 in one direction. However, the circuit of the power conversion device (inverter 12, rectifier 16) is changed as appropriate. By doing so, it can be set as the apparatus which transmits electric power bidirectionally.

  Next, the present invention will be described in more detail with reference to the following examples and comparative examples.

Example 1
In Example 1, the current and power transmission efficiency with respect to the frequency were obtained using the non-contact power transmission device 1 including the above-described non-contact power transmission circuit. FIG. 5 shows the arrangement of the coils in the configuration of the non-contact power transmission circuit used in Example 1. FIG. 6 shows the results of obtaining the current and power transmission efficiency with respect to the frequency. The power transmission efficiency here is an efficiency for outputting 1 kW, as will be described in detail later.

As shown in FIG. 5, in the contactless power transmission circuit used in Example 1, whereas the coil 4 and 3cm distance _{S 1} of the intermediate coil 22, 10 cm distance _{S 2} between the intermediate coil 22, the intermediate coil 22 and the other the distance _{S 3} of the coil 7 and 3 cm, the coil body 41 is disposed in each coil, the coil body 221, the diameter r of the coil body 221 and the coil body 71 was 20cm respectively. Moreover, the output peak voltage Vp of the primary side equipment 3 was ± 200 V, the output power P was 1 kW, and the load resistance R of the secondary side equipment 6 was 20Ω.

As described above, the input impedance viewed from the DC power source 11 and the power transmission efficiency are given based on the relationship between the voltage applied to the coil and the current flowing through the coil, and the mutual inductance is determined using the coupling coefficient and the self-inductance. Can be derived. The loss of each coil can be derived from the amount of heat generated based on the current value and the winding resistance of the coil. The derived parameters are shown in Table 1 below. Table 2 below shows the coupling coefficient between the coils set according to the arrangement of the coils. In the first embodiment, the coupling coefficient between the one coil 4 and the intermediate coil 22 adjacent to the one coil 4 is k ₀₁ , the coupling coefficient between the intermediate coils 22 is k ₁₂ , and the intermediate coil 22 adjacent to the other coil 7 is used. intermediate coil 22 and the other coil 7 adjacent the coupling coefficient between the intermediate coil 22 to k _02, whereas the coil 4 a coupling coefficient k _23, whereas adjacent to the coil 4 and the other coil 7 between the other coil 7 and the coupling coefficient between the coupling coefficient and k _13, whereas the coil 4 and the other coil 7 between was k _03.

As shown in FIG. 6, the frequency at which the maximum efficiency of the coil is 81190 Hz, while the coil current (input current) of the coil 4 is 7.60 A, while the coil current (intermediate of the intermediate coil 22 adjacent to the coil 4 is intermediate). Resonance current) is 11.35 A, the coil current (intermediate resonance current) of the intermediate coil 22 adjacent to the other coil 7 is 12.21 A, and the coil current (output current) of the other coil 7 is 7.09 A. It was. The maximum efficiency of the coil was 91.8%. As shown in Table 2, the ratio of the coupling coefficient k ₀₁ , the coupling coefficient k ₁₂ and the coupling coefficient k ₂₃ between the coils was approximately 2: 1: 2.

(Comparative Example 1)
In Comparative Example 1, a circuit similar to the non-contact power transmission circuit used in Example 1 was used except that the distance between one coil 4 and the other coil 7 was set to 10 cm without arranging the two intermediate coils 22. . FIG. 7 shows the results of obtaining the current and power transmission efficiency with respect to the frequency, and the derived parameters and the coupling coefficients between the coils are shown in Table 3 below.

  As shown in FIG. 7, the frequency at which the maximum efficiency of the coil is 87210 Hz, the coil current (input current) of the coil 4 is 22.14 A (overcurrent: 20 A or more), and the coil current of the other coil 7 ( The output current was 7.09A. The maximum efficiency of the coil was 88.2%.

(Comparative Example 2)
In Comparative Example 2, the magnetic body 222 was not disposed on each of the two intermediate coils 22, but the distance between the one coil 4 and the intermediate coil 22 and the distance between the other coil 7 and the intermediate coil 22 were each 7 cm. The same circuit as the non-contact power transmission circuit used in 1 was used. FIG. 8 shows the results of obtaining the current and the power transmission efficiency with respect to the frequency. The derived parameters are shown in Table 4 below, and the coupling coefficients between the coils are shown in Table 5 below.

As shown in FIG. 8, the frequency at which the maximum efficiency of the coil is 82180 Hz, while the coil current (input current) of the coil 4 is 7.27 A, while the coil current (intermediate of the intermediate coil 22 adjacent to the coil 4 is intermediate). Resonance current) is 16.53 A, coil current (intermediate resonance current) of the intermediate coil 22 adjacent to the other coil 7 is 14.77 A, and coil current (output current) of the other coil 7 is 7.10 A. It was. The maximum efficiency of the coil was 88.6%. As shown in Table 5, instead of using the magnetic body 222, the ratio of the coupling coefficient k ₀₁ , the coupling coefficient k ₁₂ and the coupling coefficient k ₂₃ between the coils is approximately 2: 1: 2.

(Comparative Example 3)
In Comparative Example 3, the magnetic body 222 (the shape is the same as that of the magnetic body 42) is disposed on the entire surface of one side of the coil body 221 in the two intermediate coils 22, and the distance between the one coil 4 and the intermediate coil 22 and the other coil. A circuit similar to the non-contact power transmission circuit used in Example 1 was used except that the distance between each of 7 and the intermediate coil 22 was 1 cm. FIG. 9 shows the results of obtaining the current and power transmission efficiency with respect to the frequency. The derived parameters are shown in Table 6 below, and the coupling coefficients between the coils are shown in Table 7 below.

As shown in FIG. 9, the frequency at which the maximum efficiency of the coil is 81960 Hz, while the coil current (input current) of the coil 4 is 19.93 A, while the coil current of the intermediate coil 22 adjacent to the coil 4 (intermediate) Resonance current) is 20.79 A (overcurrent: 20 A or more), and the coil current (intermediate resonance current) of the intermediate coil 22 adjacent to the other coil 7 is 28.95 A (overcurrent: 20 A or more). The coil current (output current) of 7 was 7.08A. The maximum efficiency of the coil was 69.0%. Further, as shown in Table 7, even if the distance is made closer to 3 cm to 1 cm, the magnetic body 222 (the shape is the same as the magnetic body 42) on the entire surface prevents the coupling between the coils. The ratio of the coupling coefficient k ₀₁ , the coupling coefficient k ₁₂ and the coupling coefficient k ₂₃ could not be 2: 1: 2.

  Comparing Example 1 and Comparative Example 1, in Example 1, the two intermediate coils 22 are arranged between the one coil 4 and the other coil 7, thereby eliminating the overcurrent (overheating) of the one coil 4. It was.

  Comparing Comparative Example 1 and Comparative Example 2, in Comparative Example 2, Joule loss (coil current) is obtained by arranging two intermediate coils 22 between one coil 4 and the other coil 7 to increase the number of coils. It was possible to promote the decrease and dispersion. This makes it possible to reduce the size of the circuit by reducing the weight of the winding (reducing the cross-sectional area). Furthermore, when Example 1 and Comparative Example 2 are compared, in Example 1, the magnetic body 222 is disposed in the intermediate coil 22, so that the interval between the coils is reduced, and the circuit can be reduced in size. In addition, since the self-inductance of each intermediate coil 22 increased (approximately 30%), each coil current further decreased, and the maximum efficiency of the coil was 91.8%, indicating that the power transmission efficiency was improved. I understood. Thereby, high efficiency of the circuit can be realized.

When Example 1 and Comparative Example 3 are compared, in Example 1, the magnetic body 222 is partially disposed in the intermediate coil 22, so that the coupling coefficient k ₀₁ , the coupling coefficient k _12, and the coupling coefficient between the coils are compared. coupling coefficient k a ratio of ₂₃ about 2: 1: can be 2, it was possible to increase the maximum efficiency of the coil. Thereby, high efficiency of the circuit can be realized.

  A reference example will be described with reference to FIGS.

  FIG. 10 shows a schematic system for explaining the outline of the entire contactless power transmission device including a contactless power transmission circuit as a reference example. Note that the same members as those in the embodiment shown in FIG.

  A non-contact power transmission device 51 shown in FIG. 10 has an intermediate air-core coil 52 arranged at an interval H (for example, 10 cm) instead of the intermediate coil member 21 shown in FIG. Other configurations are the same as those of the non-contact power transmission apparatus 1 shown in FIG. As the intermediate air-core coil 52, for example, a litz wire obtained by combining 228 enameled copper wires having an outer diameter of 20 cm and a wire diameter of 0.12 mm was used for the winding. The number of turns was 27 from the outer diameter of the litz wire of 3.15 mm.

  FIG. 11 shows the ratio (dB) with respect to the fundamental current of the non-contact power transmission apparatus of the reference example shown in FIG. 10 and the non-contact power transmission apparatus of the embodiment shown in FIG.

  In FIG. 11, the black bar represents the third harmonic current, the hatched side line represents the fifth harmonic current, and the white bar represents the ratio of the seventh harmonic current to the fundamental current. As shown in the figure, the ratio of the third harmonic current, the fifth harmonic current, and the seventh harmonic current is higher in the non-contact power transmission apparatus of the embodiment than the non-contact power transmission apparatus of the reference example. It is getting bigger. That is, the harmonic current that becomes a radiation noise source can be suppressed.

  For this reason, when the non-contact power transmission apparatus of the embodiment shown in FIG. 1 is used, the intermediate coil member 21 functions as a noise filter, so that it is possible to suppress radiated noise that hinders the operation of other devices, It becomes easier to clear the electromagnetic compatibility (EMC) tolerance. For example, when used as a charging device for an electric vehicle, it is possible to construct a charging device facility in a residential area or the like where an electromagnetic compatibility (EMC) tolerance is severe.

  12 shows the relationship between the frequency (kHz) and the coil efficiency (%) of the contactless power transmission device 51 of the reference example shown in FIG. 10 and the contactless power transmission device 1 of the embodiment shown in FIG. Is shown.

  12 indicates the relationship of the coil efficiency (%) to the frequency (kHz) of the non-contact power transmission device 51 of the reference example shown in FIG. 10, and the Δ mark in FIG. 12 indicates the embodiment shown in FIG. It is the relationship of the efficiency (%) of the coil with respect to the frequency (kHz) of the non-contact electric power transmission apparatus 1 of. As shown in the figure, in the non-contact power transmission device 1 of the embodiment, compared with the non-contact power transmission device 51 of the reference example, although shifted to the high frequency side, it is possible to maintain high coil efficiency. Recognize.

  For this reason, in the non-contact power transmission device 1 of the embodiment, the fine adjustment of the intermediate capacitor 23 can be applied while maintaining high efficiency, for example, in a frequency region when used as a charging device for an electric vehicle. Become.

  FIG. 13 shows the DC load voltage (V) and coil efficiency (%) of the contactless power transmission device 51 of the reference example shown in FIG. 10 and the contactless power transmission device 1 of the embodiment shown in FIG. The relationship is shown.

  In FIG. 13, the □ marks indicate the efficiency (%) of the coil with respect to the DC load voltage (V) of the non-contact power transmission device 51 of the reference example shown in FIG. 10, and the Δ marks in FIG. It is the relationship of the efficiency (%) of the coil with respect to DC load voltage (V) of the non-contact electric power transmission apparatus 1 of an Example. As shown in the figure, in the non-contact power transmission device 1 of the example, the optimum value of the DC load voltage (V) (voltage value at which efficiency reaches a peak) is higher than that of the non-contact power transmission device 51 of the reference example. It turns out that it has shifted to the high voltage side.

  For this reason, in the non-contact electric power transmission apparatus 1 of an Example, it becomes possible to reduce an inductance and to achieve weight reduction.

  The present invention relates to a non-contact power transmission circuit and a non-contact power transmission device that send power in a non-contact manner from one side (power supply side: primary side) to the other side (power supply side: secondary side). Can be used in industrial fields.

DESCRIPTION OF SYMBOLS 1, 51 Non-contact electric power transmission apparatus 2 One coil member 3 Primary side equipment 4 One coil 5 Other coil member 6 Secondary side equipment 7 Other coil 8 One capacitor 9 Other capacitor 11 DC power supply 12 Inverter 15 Load 16 Rectifier 21 Intermediate coil member 22 intermediate coil 23 intermediate capacitor 41, 71, 221 coil body 42, 72, 222 magnetic body 43, 73 metal magnetic shielding plate 52 intermediate air core coil 224 rod-shaped magnetic body

Claims (3)

A closed circuit is formed by one coil on one side and one capacitor connected in parallel or in series with the one coil to form one coil member,
While forming the closed circuit with the other coil on the other side and the other capacitor connected in parallel or in series with the other coil, the other coil member,
A closed circuit is formed by an intermediate coil and an intermediate capacitor connected in parallel to the intermediate coil to form an intermediate coil member,
A non-contact power transmission circuit in which a plurality of the intermediate coil members are arranged between the one coil member and the other coil member,
The one coil and the other coil are opposite to the coil body wound in a disk shape, the magnetic body arranged in parallel to the coil body, and the intermediate coil member of the coil body and the magnetic body. Each is composed of a metal magnetic shielding plate arranged on the outside,
The intermediate coil includes a coil body wound in a disk shape, and a magnetic body that is provided side by side on the coil body and partially covers the coil body. . The contactless power transmission circuit according to claim 1,
The magnetic body in the intermediate coil is composed of a plurality of rod-shaped or fan-shaped magnetic bodies, and the plurality of rod-shaped or fan-shaped magnetic bodies are arranged radially. circuit. The contactless power transmission circuit according to claim 1 or 2,
One power that is connected as a DC power source and converts the DC output voltage of the DC power source into an AC voltage, and the one coil is connected and driven as an inverter so that the converted AC voltage is applied to the other coil. A conversion device;
A power converter connected to the other coil, and that is driven as a converter that converts the AC voltage applied through the other coil into a DC output voltage and applies the DC output voltage to a DC load. A non-contact power transmission device.